Float tube is a generic name for a class of inflatable rafts used by anglers. Float tubes are small, lightweight vessels which are typically used by a single person to quietly fish in a body of water without submerging the angler's entire body into the water, but still submerging a portion for stability and maneuvering.
Because the operator's center of mass is lower in a float tube than in a conventional raft or boat, the float tube can be constructed from a simple automobile innertube. The operator inserts his or her legs through the hole in the innertube and submerges his or her legs and torso into the water until the underarms rest against the edges of the innertube. A small hammock-like structure can be suspended between two sides of the innertube to form a cradle for more comfortably supporting the weight of the operator's body while leaving the operator's arm free.
FIG. 1 shows a conventional, prior art float tube 10 which is circular, similar to an automobile innertube. Float tubes include any small, inflatable or otherwise lightweight, one or two-person rafts. Float tubes are commonly referred to as kick boats, pontoon boats and float boats. The float tube 10 normally has an outer sleeve-like, fabric skin 12 which fits tightly against the innertube. Typically, the skin 12 is fixedly attached to the innertube providing a surface for attachment of a seat rest 14.
FIGS. 2 and 3 show additional prior art float tubes having U-shaped and parallel pontoon configurations, respectively. The U-shaped float tube 16 shown in FIG. 2 has an inflatable bladder (not visible in FIG. 2) which is enclosed by a skin 18. The skin 18 is similar to the skin 12 of FIG. 1 and encloses the bladder of the tube 16 providing an attachment surface for a seat 20. The float tube 22 shown in FIG. 3 is made of two elongated inflatable bladders enclosed by sheet-like skins 24 and 26. The skins 24 and 26 are similar to skin 12 of FIG. 1, and provide attachment surface for support bracket 28 and seat rest 30.
Most float tubes use human power to propel the float tube along the water surface. This typically involves fins fitted to the operator's feet which are kicked in the manner of a scuba diver or a pair of oars connected to propel and guide the float tube. Conventional trolling motors are also attached to float tubes to provide propulsion.
Walden, in U.S. Pat. No. 5,090,930, shows an apparatus which wraps around the circumferential outer surface of a float tube to attach a boat motor to the rear of a float tube. The Walden apparatus includes a buoyant device to support the motor and battery due to their size and weight.
Schulz, in U.S. Pat. No. 3,324,488, shows a similar, motor attachment for rigidly affixing a motor to a foam, annular tube by rods fixed to or extending into the foam.
Cefalo, in U.S. Pat. No. 3,123,840, shows a float tube connection for attaching boat oars and a conventional boat motor to a float tube. This apparatus is large and heavy, and requires a buoyant flotation device for the motor.
Goodman, in U.S. Pat. No. 4,596,529, discloses members permanently attached to a flexible boat. A boat motor is attached to the permanent members which are flexed apart in order to insert a motor housing shaft between the members.
In U.S. Pat. No. 4,938,722, Rizley shows a motorized attachment for the fisherman's leg which propels the fisherman and float tube. A separate innertube is attached to the float tube and supports the battery supplying power to the electric motor.
U.S. Pat. No. 4,911,094 to Akers shows a very similar apparatus to that of Rizley but with the motor attached to the secondary innertube instead of the user's leg.
In Holden, U.S. Pat. No. 5,081,947, two interlocking, concave bodies fit together within the aperture of an innertube. The bodies lock together and form a seat for the fisherman, and provide pedals and a propeller for propelling the innertube.
McIntyre, in U.S. Pat. No. 3,665,534, shows a motor support framework which attaches to a fishing float. The framework supports a conventional motor attached to its rear and operated in the conventional manner by the hands of the user rotating the motor about a pivot. The framework attaches to the float tube by a pair of parallel straps encircling an edge of the tube.
All of the above described propulsion devices suffer from the defect of either too little propulsion power or too much weight and bulk. The desirable characteristics of a float tube are small size and light weight, permitting the fisherman to carry the float tube to remote locations for use where a conventional raft or row boat would be difficult to transport or possibly too large to use. Furthermore, quiet operation with sufficient power to propel a fisherman against any water currents or wind forces which may be present are highly desirable.
Since most conventional propulsion devices either have too little power to sufficiently propel a float tube user, or have too much weight to maintain one of the primary advantages of using a float tube, the need exists for a propulsion apparatus for mounting to a float tube to provide sufficient power while maintaining the weight, size and lower cost advantages of the float tube compared to conventional fishing boats.